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SELECT ERYTHROCYTE CHARACTERISTICS IN PREVIOUSLY FROZEN WHOLE BLOOD ARE DIFFERENT FROM IMMEDIATE ANALYSIS
No full textImmediate analysis of blood samples is optimal for the best representation of in vivo measurements. However, this is not always possible, and the extent to which freezing whole blood affects measurement parameters is not well understood. PURPOSE: To investigate if blood parameters are preserved when samples are frozen rather than analyzed immediately with and without the addition of a cryoprotectant. METHODS: Venous blood was analyzed immediately and divided into samples stored at ~9ºC or -70ºC. Samples stored at ~9ºC, and samples stored at -70ºC, once thawed, were analyzed immediately, and on days 1, 2, 5, and 10 post-draw or postthaw, respectively. In addition, some samples were analyzed on days 16 and 88 post-draw or post-thaw. Hemoglobin concentration (tHb), oxyhemoglobin (HbO2), carboxyhemoglobin (HbCO), methemoglobin (MetHb), and oxygen content (O2ct) were measured in sextuplicate using an OSM3 hemoximeter. Hematocrit (Hct) was measured in triplicate using microcentrifugation. In a separate group of samples, two cryoprotectants, dimethyl sulfoxide (DMSO) and glycerol, were added at concentrations of 1%, 2%, 15%, and 50% and Hct was measured. RESULTS: A significant main effect of time was observed in tHb (β = 0.006, p = 0.025), HbO2 (β = -0.344, p \u3c .001), HbCO (β = 0.025, p \u3c .001), MetHb (β = 0.388, p \u3c .001), and O2ct (β = -0.081, p \u3c .001). A significant main effect of condition was observed in all parameters (∆tHb = -1.379, ∆HbCO = 0.389, ∆MetHb = -4.52, ∆O2ct = -1.452; p \u3c .001), excluding HbO2 and Hct. A significant interaction was observed in all parameters (coeff: tHb [0.017], HbO2 [0.227], HbCO [-0.021], MetHb [- 0.169], O2ct [0.077]; p \u3c .001), excluding Hct. We were unable to measure Hct because samples did not separate with microcentrifugation post-thaw. At cryoprotectant concentrations of 15% and 50%, some separation for Hct was observed, more so with glycerol than DMSO. CONCLUSION: Whether samples were frozen or not, stability was only observed in Hct stored at ~9ºC. Differences in post-thaw data suggest that freezing whole blood does not provide an optimal representation of in vivo measurements. Additionally, while cryoprotectant use for preservation of Hct may be possible, its use may not be viable for blood parameter analysis. Thus, further investigations are needed to develop alternative storage methods
AN INTEGRATED LIFESTYLE PROGRAM ON WEIGHT, FUNCTIONAL CAPACITY, AND EXERCISE SELF-EFFICACY AMONG BREAST CANCER SURVIVORS
No full textReduced functional capacity (FC) and excess body weight predict breast cancer (BC) prognosis, yet many breast cancer survivors (BCS) exhibit diminished FC and/or have overweight/obesity. To improve BC control efforts, interventions targeting improvements in FC alongside reductions in body weight are needed. PURPOSE: To determine the impact of an integrated lifestyle weight loss program on weight, FC, fatigue, and exercise self-efficacy among BCS. METHODS: Data from 15 BCS with overweight or obesity (Age= 55.3±5.7; 100% Female; 93% White, 80% non-Hispanic) who participated in a 13-week group-based behavioral weight loss program were used in this secondary data analysis. Participants were instructed to adhere to a 4:3 intermittent fasting protocol composed of a modified fast (500 kcal) on 3 days/week with ad libitum intake the other 4. Participants were offered a weekly virtual, one-hour group support class with a registered dietician, a weekly one-hour, in-person exercise session with a Cancer Exercise Program trainer, and two additional at-home, virtual sessions prescribed by their trainer. The exercise support aimed to increase participants’ activity by ≥100 min/wk up to a total of 150 min/wk. Assessments were completed at baseline and week 13. FC was assessed via the 6-minute walk test (6MWT) and the ‘Sit-to-Stand’ test (STS), fatigue by the FACIT Fatigue scale, exercise self-efficacy was measured using the BARSE, and weight was calculated via a calibrated scale. Missing data were addressed via listwise deletion. As this study is insufficiently powered for statistical inference, only effect size estimates and confidence intervals (CI) are provided. RESULTS: Across the 13-week intervention, participants exhibited small to moderate improvements in weight (Mean Difference= 4.1kg, d=0.31, 95% CI [-0.4-1.0]), self-reported fatigue (d=0.42, 95% CI [-0.3-1.1]), and exercise self-efficacy (d=0.36, 95% CI [-1.1-0.4]. Moderate to large improvements were observed on the 6MWT (d=0.81, 95% CI [-1.6-0.0] and the STS (d=0.75, 95% CI [-1.5-0.0]. CONCLUSION: The integrated lifestyle weight loss program reduced body weight and improved FC, exercise self-efficacy and fatigue. These findings underscore the integrated program\u27s preliminary efficacy in improving key health indicators relevant to BC survivorship. Financial Support: This work was supported by grants from the National Institutes of Health: R01 CA258766, K01 HL145023, K01 HL 161417, K99 CA287061, T32 DK120521, the contents do not represent the views of the United States Government. CHRONO-EXERCISE CONSOLIDATES SLEEP K. Pitha, H. Chargui, B. Bruch, S. Negaard, M. Engelke, B. Roberts, E.E. Schmitt University of Wyoming, Laramie, Wyoming Circadian rhythms are the biological process that helps to regulate the sleep-wake cycle. These rhythms are regulated by the suprachiasmatic nucleus (SCN) located in the anterior hypothalamus in the brain. Disrupted circadian rhythms can lead to sleep disturbances and poor sleep habits over time. PURPOSE: The purpose of this study is to use exercise as a method of re-entraining circadian rhythms in mice through forced treadmill running and sleep analysis. METHODS: This work was approved by the University of Wyoming IACUC. In this study we took male (n=8) and female mice (n=4) and studied their sleep rhythm during exercise entrainment. The sleep system was non-invasive and continuously monitored the mice for seven days pre-exercise and seven days during exercise. The exercise training protocol mimicked ACSM guidelines for moderate intensity and was as follows: Days 1 – 7 warm –up at 8m/min for 5 minutes then 13 m/min for 35 minutes. Exercise occurred 30 minutes after lights off for males and females. RESULTS: Male mice had more consolidated sleep with early active period exercise as shown through increased bout length, total sleep, dark period sleep, and the decreased number of bouts. Late active period exercise was also done with male mice and results showed that the total bout length and day sleep decreased suggesting that exercise at this time does not carry the same benefits as early exercise. Females respond differently than males in most instances but responded similarly to early chrono-exercise with an increase in sleep and sleep duration. CONCLUSION: Exercise is a viable and cost-effective method to help with sleep. It is a natural way to regulate the circadian rhythm, promoting deeper and more restful sleep. Continuation of this work will shed light to the neural mechanisms underlying how sleep is consolidated in exercised entrained mice. This work was supported by NIH Grant 2P20GM1213100
WILL AVERAGE AND PEAK JUMP-POWER BE AFFECTED DURING THE WEEK OF A COMPETITIVE SOCCER SEASON?
No full textJump power is a vital component for an athlete because generating as much power as possible in a short amount of time is a fundamental part of athletic performance. Peak power measures the maximum explosive force that can be created while average power represents the overall power during the jumping phase. Both measurements show the athlete’s ability to generate quick, powerful bursts of force and sustained power. PURPOSE: The purpose of this study is to evaluate the changes in jump power of collegiate soccer players during one week of the competitive season (August-November) to see if the number of minutes played in games coupled with practices impacts peak and average jump power. METHODS: The present investigation spanned three different assessment days (Monday, Thursday, and the following Monday). For each day, the athletes (n=13) performed three countermovement jumps with their hands on their hips. RESULTS: From Monday to Thursday, there were no significant differences in average power (z=-0.314, p=0.753) with the median average power decreasing from 803.000 watts to 800.000 watts. There was a significant difference in peak power (z=-1.992, p=0.046) with the median peak power decreasing from 4148.00 watts to 3453.00 watts. From Thursday to Monday, there was no significant difference in average power (z=-1.491, p=0.136) with the median average power decreasing from 800.00 watts to 792.00 watts. There was no significant difference in peak power (z=-0.943, p=0.345) with the median peak power decreasing from 3453.00 watts to 3173.00 watts. From Monday to Monday, there was a significant decrease in both average and peak power. Median average power decreased from 803.00 watts to 792.00 watts (z=-2.341, p=0.019). Median peak power decreased from 4148.00 watts to 3173.00 watts. CONCLUSIONS: The study revealed that from one Monday to the following Monday, the team’s vertical jump performance for power decreased. This study also revealed that the soccer players are not at their peak performance for the weekend games, potentially due to high volumes of practicing and lifting during the week
THE EFFECT OF MUSCLE OXYGENATION ON NEUROMUSCULAR EFFICIENCY AND FORCE COMPLEXITY
No full textLimiting oxygen delivery during steady-state exercise gradually increases muscle excitation at submaximal forces, suggesting a time-dependent effect of oxygenation on neuromuscular efficiency (NME). Whether sustained reductions in muscle oxygen saturation (SmO2) from rest impacts NME and motor output characteristics of subsequent voluntary contractions is unknown. PURPOSE: We tested the hypothesis that sustained reductions in SmO2 from rest would decrease NME and force complexity of submaximal contractions. METHODS: Twenty-nine participants (12M/17F, 22 ± 3 yrs) performed submaximal dorsiflexion under control conditions (CON) and at 70%, 60%, and 50% SmO2. Leg circulatory occlusion was used to elicit target SmO2 of the tibialis anterior muscle at rest. After 3 minutes at the target SmO2 (via cuff-pressure manipulation), participants performed 6 contractions (6s contraction, 14s relaxation) at 50% maximal voluntary contraction (MVC). NME was calculated as force divided by the root mean square of electromyography signals normalized to MVC (N-RMS). Force complexity was assessed by detrended fluctuation analysis (DFA) and approximate and sample entropy (ApEn and SampEn). Data from the final three contractions were averaged, and comparisons were made using linear mixed-effects models and Tukey’s tests. RESULTS: There was a significant effect of SmO2 on N-RMS and NME (both, p \u3c 0.001; Figure 1) as well as DFA, ApEn, and SampEn (all, p \u3c 0.05). NME was significantly lower in all desaturated conditions compared to CON (all, p \u3c 0.05, Figure 1). Greater desaturation led to greater decreases in NME (all p \u3c 0.05; Figure 1) except for 50% (n = 9). At 60%, DFA was higher (+2%; p \u3c 0.05) and ApEn and SampEn were lower (-32% and -30%; both, p \u3c 0.05) than CON. CONCLUSION: Reducing SmO2 decreases subsequent NME and force complexity, supporting that muscle oxygenation influences muscle activation characteristics and motor unit control of submaximal voluntary contractions
RESTING LESS: ASSOCIATIONS BETWEEN WEIGHT STATUS AND SLEEPING BEHAVIORS AMONG ELEMENTARY SCHOOL CHILDREN.
No full textSleep is essential for overall health. Insufficient sleep has been linked with numerous developmental deficits in school age children. However, less is known about how sleeping behaviors distribute across weight categories in youth populations. PURPOSE: Examine different measures of sleep on school nights and weekends by weight status and physical activity. METHODS: The current study collected data from February 2023 to May 2024. Children in K-5th grade (N=132), attending public schools in Little Rock, Arkansas wore accelerometers on their hip to estimate sleep and measure physical activity 24 hours/day for 7 days. Anthropometric data was collected, and participants were classified into four weight classifications based on BMI percentiles: normal weight (99th). RESULTS: Participants recorded more total sleep on weekends compared to school nights (531.9 min/night vs 500.4: p 9 hours on weekends with severely obese participants averaging just over 8 hours. Our findings suggest that weight status is independently related to total time in bed, weekend makeup sleep, and vigorous physical activity. Future longitudinal analyses will allow for a better understanding of the relationship between sleep and obesity as children age
Strength Training Can Modulate Urinary Adipokine Levels In Healthy Young Males
Get PDFInternational Journal of Exercise Science 18(2): 107-118, 2025. Adipose tissue stores energy in fat-rich adipocytes, which can produce and release several adipokines and modulate body metabolism. Exercise may induce adipokine production in adipocytes; however, the relationship between the two remains unclear. Few studies have shown the relationship between adipokines and strength training. Thus, we aimed to evaluate the acute and chronic effects of strength training (ST) on urinary adiponectin, leptin, and resistin levels. Twelve untrained young men (23.42 ± 2.67 years) were included in this study. Body composition was evaluated at baseline and after completing of the training protocol using densitometry. Training protocol consisted of three exercises with three sets of 65% of one-repetition maximum (1MR) with a pause of 90 s between sets, each exercise lasting 5 s (2 s concentric / 3 s eccentric). The sessions were carried out three times a week for 10 weeks. Urine was collected during the pre- and post-training in the first and 30th session. Adipokine levels were determined by ELISA. Urinary levels of leptin acutely increased after the first ST session, and after the last ST session. Chronic changes in the leptin levels were also found when comparing the values before the last ST and before the first ST session. Urinary adiponectin levels changed in the comparison of values before and after the last session. There was a significant increase in the adiponectin levels when comparing values after the first and last ST sessions. The levels of resistin chronically increased. Strength training can induce acute and chronic changes in urinary levels of adipokines
UA19/16/5/16 Athletic Media Relations - Volleyball Film/ideo/Audio File
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Prevalence of Exercise Dependence Among High-Intensity Functional Training Practitioners: A Cross-Sectional Analysis
Get PDFInternational Journal of Exercise Science 18(4): 206-214, 2025. The objective was to explore the prevalence of exercise dependence (ED) risk among regular HIFT exercisers. Secondary objectives include exploring the prevalence of injuries within this population and examining the potential association between ED risk and injury prevalence. This cross-sectional study was conducted in a city in southern Brazil and included HIFT practitioners. ED was evaluated using the Exercise Dependence Scale-Revised (EDS-R). The primary outcome was the prevalence of ED risk. The final analysis included 64 HIFT practitioners, of whom the majority were female (n = 35; 54.7%). The mean EDS-R score was 67.6 ± 14.7. A weak positive correlation was found between the duration of HIFT practice (r = 0.312) and weekly training frequency (r = 0.442) with EDS-R scores. Categorically, 25.0% (n = 16) of participants were classified as being at risk for ED, 60.9% (n = 39) as symptomatic non-dependent, and 14.1% (n = 9) as asymptomatic non-dependent. The prevalence of injuries among participants was 32.8% (n = 21). The mean EDS-R score was 71.0 ± 14.4 for participants with a history of injury and 65.9 ± 14.7 for those without a history of injury. The effect size, measured by Cohen\u27s d, was 0.35 (95% CI: -0.19 to 0.89), indicating no significant difference between the two groups. A high prevalence of ED was observed among HIFT practitioners. Raising awareness of the risk of developing this pathological behavior may help in detection of symptoms and the implementation of preventive and interventional strategies
The Associations Between Acute High-Intensity Exercise, Perceived Energy Levels, and Cognition
Get PDFHigh-intensity exercise has been theoretically proposed to enhance hippocampal-dependent cognition and impair prefrontal cortex (PFC)-dependent cognition immediately following exercise. However, empirical evidence has been inconsistent in supporting these effects. PURPOSE: This study aimed to reconcile discrepancies between theoretical predictions and empirical findings by exploring the effects of acute high-intensity exercise on different types of cognition. It also examined the potential role of psychological factors, including motivation, perceived energy availability, and perceived energy cost, in the exercise-cognition relationship. METHODS: Fifty-five healthy young adults (mean age = 20.4 years + 1.8) participated in a within-subject experiment involving five visits. The first visit included a maximal treadmill exercise test to determine participants’ maximal heart rate and endurance capacity. The maximum heart rate data obtained during this visit were used to calculate the target exercise intensity for the high-intensity condition using the heart rate reserve formula. Visits 2–5 occurred in a random order and involved a 20-minute session of high-intensity exercise or standing (rest) on a treadmill, followed by tasks assessing hippocampal- or PFC-dependent cognition. Immediate and delayed cognitive assessments were conducted via n-back (PFC-dependent) and mnemonic similarity tasks (hippocampal-dependent), with a 20-minute delay between the initial and subsequent assessments. Psychological factors were measured using seven self-reported questions after the exercise/rest condition and before initial cognitive testing. For the PFC-dependent task, a 2 (Condition: EX vs. Rest) × 2 (Time: 1st vs. 2nd Assessment) × 2 (nBack: 2 vs. 3) repeated measures ANOVA was employed, with proportion accuracy as the outcome. For the hippocampal-dependent task, a 2 (Condition: EX vs. Rest) × 2 (Time: 1st vs. 2nd Assessment) repeated measures ANOVA was conducted, with separate analyses for item recognition and behavioral pattern separation. Psychological factors influencing cognition were evaluated using paired t-tests and regression analyses. RESULTS: For the n-back tasks, there were no significant main effects or interactions for Condition, Time, or their combinations (all ps \u3e .05), except for a main effect of nBack, F(1,54) = 62.172, p \u3c .001, n2p= .535. For item recognition and behavioral pattern separation, there were no significant main effects or interactions (all ps \u3e .05). While participants reported higher mental energy levels after exercise compared to rest, t(54) = 2.41, p = .02, this increase did not correspond to changes in cognitive outcomes (all ps \u3e .05). CONCLUSION: These findings challenge theoretical predictions and highlight the need for further exploration of psychological mechanisms through which acute exercise may influence cognition
Effects Of NMES On EMG-EMG Coherence Across Glenohumeral Muscles During Fatigue In Rotator Cuff Disease
Get PDFRotator cuff disease (RCD), a common pathology of shoulder pain, can be attributed to muscle weakness and altered humeral head stability, particularly during neuromuscular fatigue. Electromyographic (EMG)-EMG coherence quantifies shared oscillatory input between motoneuron pools, providing insight into motor control deficiencies in RCD. PURPOSE: To investigate the effects of neuromuscular electrical stimulation (NMES) on EMG-EMG coherence across glenohumeral muscles during fatigue in RCD. METHODS: Eight participants with RCD (39 ± 19 yrs) underwent two sessions separated by 72 hrs. Intramuscular EMG was recorded from the supraspinatus (SS), and surface EMG was recorded from the infraspinatus (IS) and middle deltoid (MD) of the painful shoulder. Baseline coherence was recorded for 30s at 25% maximal voluntary contraction (MVC) at 30° scaption before treatment. In session 1, participants received a sham treatment (0 mA) for 10 min. In session 2, NMES was applied at maximal tolerable intensity (30Hz; 0.2ms; 4s-on, 6s-off) for 10 min. Following each treatment, a sustained isometric 25% MVC task was performed until endurance limit. Z-transformed pooled coherence in the delta (2-5 Hz) and beta (15-35 Hz) bands for SS-IS, SS-MD, and IS-MD pairs were compared across the first and last 30s of fatigue tasks with a 2-way repeated measures ANOVA with Bonferroni post-hoc tests. Change in coherence between sessions was compared using paired t-tests. RESULTS: No significant difference in baseline coherence between sessions. There was a significant increase in SS-IS delta-band coherence with fatigue following NMES (initial: 0.14 ± 0.03, final: 0.20 ± 0.04; p = 0.002), but no significant change following the sham. Beta-band coherence increased with fatigue in both sessions, but to a greater degree in session 2 than in session 1 for both SS-IS (Δsham: 0.02, ΔNMES : 0.07; p = 0.04) and SS-MD (Δsham: 0.02, ΔNMES : 0.08; p = 0.02). No significant difference in IS-MD coherence between sessions. CONCLUSION: NMES before a fatiguing task caused an increase in SS-IS and SS-MD coherence, reflecting an excitability effect on the corticospinal tract. NMES enhances coherence across shoulder muscles, potentially improving joint stability and developing neuromuscular rehabilitation strategies for fatigue-related performance declines